What will 5G be? What it will not be is an incremental advance on 4G. The previous four generations of cellular technology have each been a major paradigm shift that has broken backward compatibility. Indeed, 5G will need to be a paradigm shift that includes very high carrier frequencies with massive bandwidths, extreme base station and device densities, and unprecedented numbers of antennas. However, unlike the previous four generations, it will also be highly integrative: tying any new 5G air interface and spectrum together with LTE and WiFi to provide universal high-rate coverage and a seamless user experience. To support this, the core network will also have to reach unprecedented levels of flexibility and intelligence, spectrum regulation will need to be rethought and improved, and energy and cost efficiencies will become even more critical considerations. This paper discusses all of these topics, identifying key challenges for future research and preliminary 5G standardization activities, while providing a comprehensive overview of the current literature, and in particular of the papers appearing in this special issue.

What Will 5G Be

Massive multiple-input multiple-output (MIMO) wireless communications refers to the idea equipping cellular base stations (BSs) with a very large number of antennas, and has been shown to potentially allow for orders of magnitude improvement in spectral and energy efficiency using relatively simple (linear) processing. In this paper, we present a comprehensive overview of state-of-the-art research on the topic, which has recently attracted considerable attention. We begin with an information theoretic analysis to illustrate the conjectured advantages of massive MIMO, and then we address implementation issues related to channel estimation, detection and precoding schemes. We particularly focus on the potential impact of pilot contamination caused by the use of non-orthogonal pilot sequences by users in adjacent cells. We also analyze the energy efficiency achieved by massive MIMO systems, and demonstrate how the degrees of freedom provided by massive MIMO systems enable efficient single-carrier transmission. Finally, the challenges and opportunities associated with implementing massive MIMO in future wireless communications systems are discussed.

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An Overview of Massive MIMO: Benefits and Challenges

A system, method, apparatus and computer program product for providing location based functions and mobile e-commerce comprising a central processing unit including a processor, a storage device, and programming stored in the storage device, a display device, an audio input device, an audio output device, a communications module, a commerce module, an image module, and a location module. The programming controls the operation of the present invention to provide functions based on location data, to facilitate commercial exchanges by wirelessly exchanging payment and product information with venders, to identify services such as venders meeting selection criteria, to wirelessly exchange select information with other users and systems, to restrict and/or monitor the use of the device based on authorized user parameters, selecting one of a plurality networks through which to communicate, detecting a trigger for performing an action based on a change in location and sensed data, storing a voice annotation with a computer data file, determining service providers and associated communication parameters, contemporaneously maintaining a wireless voice and data link, providing a system for selecting and delivering mobile advertisements, and many other functions and services that are described herein.

System, method, and computer program product for providing location based services and mobile e-commerce

There is considerable pressure to define the key requirements of 5G, develop 5G standards, and perform technology trials as quickly as possible. Normally, these activities are best done in series but there is a desire to complete these tasks in parallel so that commercial deployments of 5G can begin by 2020. 5G will not be an incremental improvement over its predecessors; it aims to be a revolutionary leap forward in terms of data rates, latency, massive connectivity, network reliability, and energy efficiency. These capabilities are targeted at realizing high-speed connectivity, the Internet of Things, augmented virtual reality, the tactile internet, and so on. The requirements of 5G are expected to be met by new spectrum in the microwave bands (3.3-4.2 GHz), and utilizing large bandwidths available in mm-wave bands, increasing spatial degrees of freedom via large antenna arrays and 3-D MIMO, network densification, and new waveforms that provide scalability and flexibility to meet the varying demands of 5G services. Unlike the one size fits all 4G core networks, the 5G core network must be flexible and adaptable and is expected to simultaneously provide optimized support for the diverse 5G use case categories. In this paper, we provide an overview of 5G research, standardization trials, and deployment challenges. Due to the enormous scope of 5G systems, it is necessary to provide some direction in a tutorial article, and in this overview, the focus is largely user centric, rather than device centric. In addition to surveying the state of play in the area, we identify leading technologies, evaluating their strengths and weaknesses, and outline the key challenges ahead, with research test beds delivering promising performance but pre-commercial trials lagging behind the desired 5G targets.

5G : A tutorial overview of standards, trials, challenges, deployment, and practice

Cloud Radio Access Network (C-RAN) is a novel mobile network architecture which can address a number of challenges the operators face while trying to support growing end-user's needs. The main idea behind C-RAN is to pool the Baseband Units (BBUs) from multiple base stations into centralized BBU Pool for statistical multiplexing gain, while shifting the burden to the high-speed wireline transmission of In-phase and Quadrature (IQ) data. C-RAN enables energy efficient network operation and possible cost savings on baseband resources. Furthermore, it improves network capacity by performing load balancing and cooperative processing of signals originating from several base stations. This paper surveys the state-of-the-art literature on C-RAN. It can serve as a starting point for anyone willing to understand C-RAN architecture and advance the research on C-RAN.

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Cloud RAN for Mobile Networks—A Technology Overview

This paper describes a FPGA-based verification methodology for the image signal processor (ISP) of system-on-chip (SoC) type CMOS image sensor. To make a verification environment, the complete ASIC prototyping system, the ARM7 TDMI CoreTile board and external interface boards — the sensor board, the USB board and the switch board — are used. As a verification method, 4-step verification strategy comprised of ARM-core based platform verification, system verification, algorithm verification and performance verification is used. Through this method, the 2M-pixel/3M-pixel ARM-based ISP of CMOS image sensor is verified very effectively before tape-out.

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FPGA-based verification methodology of SoC-type CMOS image signal processor

The present invention relates to a communication technique to fuse an Internet of things (IoT) technology and a fifth-generation (5G) communication system to support a higher data transmission rate than a 4G system; and a system thereof. The present invention is able to be applied to an intelligent service (for example, a service relating to a smart home, a smart building, a smart city, a smart or connected car, health care, digital education, retail sales, security, safety, etc.) based on a 5G communication technology and an IoT-related technology. According to the present invention, a method to provide a service to a terminal comprises: a step of receiving a service request with respect to a second terminal from a first terminal; a step of checking whether or not the second terminal is in a power saving mode; and a step of transmitting an early media service to the first terminal based on information related to the power saving mode of the second terminal when the second terminal is in the power saving mode.

Method and device for providing a service for a terminal in a wireless communcation system

Geometry-based stochastic channel models have been developed and refined over time by a number of research groups such as 3GPP, 3GPP2, ITU and the WINNER initiative. Traditional channel model is a two-dimensional (2-D) channel model, where an elevation angle of each signal path is always assumed to be zero. While such an approach is acceptable for evaluating performance of systems with horizontally placed linear antenna arrays, modeling of elevation angles is necessary when evaluating a massive MIMO or FD-MIMO technology utilizing a 2-D antenna array. In 3GPP, a study has been finalized the details and the following key parameters are takes into account the wireless channel propagation in the elevation direction as well as the azimuth direction; height dependent pathloss generation, correlation of large scale parameters, and statistical distribution of elevation components. This paper discusses spatial channel characteristics of vertical domain as well as horizontal domain under different 2-D active array configuration. Impact on separate and full channel measurement and feedback for horizontal and vertical antennas also discusses. Furthermore, we recommend the design principle of codebook for 2-D active array which impacts on system performance.

3-Dimensional channel characteristics on 2-dimensional active array antennas

This paper demonstrates if the utilization of short-term channel information, i.e. channel state information (CSI) feedback, is beneficial in the coordination of multiple evolved Node Bs (eNBs) even with the practical non-ideal backhaul. Two CSI feedback delivery schemes, namely user equipment-specific and cell-specific CSI process configuration schemes, are addressed and compared. From the comparison, it is observed that the cell-specific CSI process configuration scheme exhibits acceptable performance with small overheads. Based on the cell-specific CSI process configuration, it is shown that the short-term channel information conveyance through the non-ideal backhaul is factually feasible. In addition, simulation results comparing performance of the inter-eNB coordinated multi point (CoMP) operations with short-term/long-term channel information and only with long-term channel information, verify that the use of the short-term channel information is advantageous. Finally, a signaling model for inter-eNB CoMP using short-term/long-term channel information is illustrated based on the X2 application protocol.

Coordination of multiple eNBs using short-term channel information

An organic light-emitting device including: a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode, the organic layer including an emission layer, wherein the organic layer includes a compound represented by Formula 1: When the compound of Formula 1 is used as an electron transport material, an organic light-emitting device including the compound may have high efficiency, low driving voltage, high brightness, and long lifespan

Younsun Kim

Papers

FPGA-based verification methodology of SoC-type CMOS image signal processor

Method and device for providing a service for a terminal in a wireless communcation system

3-Dimensional channel characteristics on 2-dimensional active array antennas

Coordination of multiple eNBs using short-term channel information

Compound and organic light-emitting device